Related papers: What Does the Milky Way Look Like?

We present a map of the spiral structure of the Galaxy, as traced by molecular CS emission associated with IRAS sources which are believed to be compact HII regions. The CS line velocities are used to determine the kinematic distances of…

We have measured the positions of large numbers of H II regions in four nearly face-on, late-type, spiral galaxies: NGC 628 (M 74), NGC 1232, NGC 3184 and NGC 5194 (M 51). Fitting log-periodic spiral models to segments of each arm yields…

Our Galaxy is a barred spiral. Recent work based on the COBE NIR data implies a small bulge-bar and a disk with a short scale-length. The corotation radius of the bar is in the range 3-4.5 kpc. The stellar density distribution beyond the…

From the inception of radio astronomy, the study of the Interstellar Medium has been both aided and frustrated by one fact: we are right within it! Our embedded perspective is favourable to observing kinematic and structural details that…

The Milky Way is made up of a central bar, a disk with embedded spiral arms, and a dark matter halo. Observational and theoretical constraints for the characteristic parameters of these components will be presented, with emphasis on the…

We have measured the distance to the massive star-forming region W3OH in the Perseus spiral arm of the Milky Way to be 1.95 $\pm$ 0.04 kilo-parsecs ($5.86\times10^{16}$ km). This distance was determined by triangulation, with the Earth's…

Observations of HI published in 1957 by Westerhout and Schmidt were presented as showing a global face-on view of spiral structure in the Milky Way. Since then many studies have attempted to improve on the early map, perhaps presupposing…

We have identified a spiral arm lying beyond the Outer Arm in the first Galactic quadrant ~15 kpc from the Galactic center. After tracing the arm in existing 21 cm surveys, we searched for molecular gas using the CfA 1.2 meter telescope and…

In this paper we introduce a new method for analysing Milky Way phase-space which allows us to reveal the imprint left by the Milky Way bar and spiral arms on the stars with full phase-space data in Gaia Data Release 2. The unprecedented…

Much of our effort in understanding the long-term evolution and morphology of the Milky Way and other galaxies has focused on the equilibrium of its luminous disk. However, the interplay between all components, seen and unseen, is a major…

Studying our Galaxy, the Milky Way (MW), gives us a close-up view of the interplay between cosmology, dark matter, and galaxy formation. In the next decade our understanding of the MW's dynamics, stellar populations, and structure will…

Morphology is the starting point for understanding galaxies. Elmegreen et al. classified spiral galaxies into flocculent, multiple-arm, and grand-design galaxies based on the regularity of their spiral arm structure. With the release of a…

Like the majority of spiral galaxies, the Milky Way contains a central non-axisymmetric bar component. Our position in the Galactic plane renders it rather hard to see, but also allows us to make measurements of the bar that are completely…

In an effort to improve our understanding of the spiral arm structure of the Milky Way, we use Classical Cepheids (CCs) to increase the number of young tracers on the far side of the Galactic disk with accurately determined distances. We…

We compare the observed radial velocity of different arm tracers, taken near the tangent to a spiral arm. A slight difference is predicted by the density wave theory, given the shock predicted at the entrance to the inner spiral arm. In…

The arm structure of the Milky Way remains somewhat of an unknown, with observational studies hindered by our location within the Galactic disc. In the work presented here we use smoothed particle hydrodynamics (SPH) and radiative transfer…

Aims: Our aim is to provide an observational view of the old Disc structure of the Milky Way galaxy using the distribution of red clump stars. The spiral arms, warp structure, and other asymmetries present in the Disc are re-visited using a…

Spiral arms shown by different components may not be spatially coincident, which can constrain formation mechanisms of spiral structure in a galaxy. We reassess the spiral arm tangency directions in the Milky Way through identifying the…

From the Sun, a look at the edge of each spiral arm in our Milky Way (seen tangentially, along the line of sight) can yield numerous insights. Using different arm tracers (dust, masers, synchrotron emission, CO gas, open star clusters), we…

Cosmologists have often considered the Milky Way as a typical spiral galaxy, and its properties have considerably influenced the current scheme of galaxy formation. Here we compare the general properties of the Milky Way disk and halo with…